Stacking seal



April 30, 1968 TETENS 3,380,127

STACKING SEAL Filed Jan. 5, 1967 frza ezz av United States Patent York Filed Jan. 5, 1967, Ser. No. 607,561 8 Claims. (CI. 24-23) ABSTRACT OF THE DISCLOSURE A band strapping seal having step-shaped deformations formed in its free ends to facilitate stacking.

This invention relates to the art of seals or clips of a type employed for joining together overlapping strap ends and particularly relates to an improved seal or clip of the stacking or nesting type which can be conveniently temporarily secured in a nested stack for interlocking engagement with each other for handling facilitiy.

When using seals in a combination strapping tool of a type which performs the functions of tensioning the strap, sealing the overlapping strap ends of the strap after it is formed into a tensioned loop and shears the supply strap end from the strap loop, such a tool is ordinarily provided with a magazine for containing a plurality of seals nested together in a stack. If the seals are provided in bulk, it is necessary for the operator to nest the seals in a stack and position them in the magazine. To avoid this task, seals are supplied by the manufacturer in prearranged stacks and commonly held together by means of a wire which extends through aligned holes punched in the centers of the back plates of the seals.

There are certain problems associated with this type of a stack utilizing a wire to hold the individual seals together and, so, another type of seal which has been developed is one which can be stacked with mating seals by detent engaging portions of adjacently positioned legs of seals which are nested with each other. Even with this type of seal, there are known disadvantages, particularly relating to their manufacture because they require close tolerance of the detent portions to insure easy separation of one seal from another in a stack during use, but sufiicient retention ability to maintain the seals in a nested stack before use.

It is an object of this invention to provide an improved nesting or stacking seal of the interlocking type which has an interlocking engagement between seals of a stack which adequately holds together the stacked seals, but still allows easy removal of one from the stack, and is of a type which can be manufactured readily with the ability to maintain required tolerances.

In order to accomplish this objective, each leg of a seal is provided with a double stepped depression along one surface which projects as a double step along its opposite surface in a corresponding pattern. The double step arrangement is included centrally of two cam surfaces against which seals interlocked by means of adjacent stepped regions must be cammed in order to slide and remove one stacked seal from engagement with another. This configuration lends itself to formation by means of a simple punch and die means construction which provides accurate seal formation with close and consistent tolerance control.

Other objects and advantages of the invention should become apparent from the following description upon reference to the accompanying drawings in which:

'FIG. 1 shows a perspective view of a preferred form of seal or clip embodying the invention;

FIG. 2 is an end view of a plurality of seals of the type 3,380,127 Patented Apr. 30, 1968 shown in FIG. 1 nested together with their legs in interlocking engagement with each other;

FIG. 3 is an enlarged cross-sectional view of the legs of two seals in stacked interlocking engagement with each other;

FIG. 4 shows an enlarged side view of a portion of a seal edge as viewed along the line of 4-4 of FIG. 1;

FIG. 5 shows a bottom edge view of the two stacked seals of FIG. 3 as viewed along the line 55 of FIG. 3 and FIG. 6 shows a perspective view of the working portions of a punch and die which can be employed to impart to the seals the two step portions which provide an interlock between nested seals.

As shown in FIG. 1, the seal 1 embodying the invention consists of a back plate or bridge 2 which connects between two flanges or leg portions 3 and 4 along folded corners 5 and 6. The legs 3 and 4 are downwardly divergent a slight amount to permit nesting of one seal upon another.

Each seal leg 3 and 4 is provided with an interlocking region 7 which is deformed in such a manner as to have on each of their front faces two cam surfaces 8 and 9 which slope inwardly toward two step portions 10 and 11. The step portion 10 is connected between a shoulder 12 and another shoulder 13. The step portion 11 is connected between the shoulder 13 and the edge 14 of the seal leg. As more clearly indicated in FIGS. 2 and 3, each shoulder 12 corresponds to a shoulder 12a formed on the rear face of the leg and each shoulder 13 corresponds to a shoulder 13:: formed on the rear face of the leg. The spacing of these shoulders with respect to each other is such that the seals interlockingly nest with each other when a shoulder 13a on a top seal engages a shoulder 12 on the seal stacked beneath it. This interlocking can be accomplished by placing one seal 'astride the other and pressing them together. This will cause the seal legs 3 and 4 to deflect slightly to allow this engagement of the shoulders and steps. When a plurality of seals are stacked together, they appear as shown in FIG. 2. It should be noted that the interlocking portions of adjacent seals are between the shoulders 13am on the top seal and the shoulders 12 on the lower seal in a stack. Although shoulders 12a and 13 are formed in the legs due to the convenient manner of punch and die forming, they serve no other specific purpose. It is essential only that there be shoulters 13a on the inner faces of the legs which are closer to the lower edges of the legs as compared to the shoulders 12 which are further removed away from the lower edges of the legs on the outer faces of the legs.

In addition to the corresponding portions mentioned on the front and rear faces of the legs, there are also step portions 104: and 11a corresponding to step portions 10 and 11 and there are corresponding cam surfaces 8, 8a and 9, 9a.

FIG. 6 shows a punch and die which can be used to produce the shape required for interlocking as described. The punch 15 has a male shape corresponding to the interlocking region shown in FIGS. 1 and 4 while the die 17 is provided with a corresponding female shape 18.

When the punch 15 and the die 17 are brought together against a seal leg 3 or 4 with the seal properly located between them, the interlocking region 7 is formed on a seal leg, both front and back.

When the seals are employed in a magazine of a strapping tool in readiness for use, suitable mechanism is provided for shifting the bottom seal of a stack endwise from the stack into the joint forming mechanism which is actuated to deform the seal into encircling and interlocking engagement with overlapping binder strap ends. As the seal is shifted endwise, the camming surfaces 8a and 9a on one seal directly opposite the camming surfaces 8 and 9 on the immediately adjacent stacked seal cam against each other to deflect the seal legs 3 and 4 and allow passage of the interlocking regions 7 of the adjacent seals. Depending upon which direction the seal is shifted endwise determines which camming surfaces 8 and 8a or 9 and 9a cam against each other. A suitable angle A which represents the slope of the camming surfaces has been found to be about 13 degrees with a depth dimension B of about .006 inch and a depth dimension C of about .012 inch on a seal of about one inch length, about one-quarter inch leg length and of about .020 inch thickness low carbon steel material.

Further, with the seal construction shown, the punch 15 and die 17 construction is of simple and effective design, whereby consistently accurate shaping and tolerance control is possible in the manufacture of the seals to make the seal a very practical commercial design.

Although only a single embodiment of the invention has been shown and described, it should be clearly understood that the invention can be manufactured in many different Ways without departing from the true scope of the invention as defined by the appended claims.

I claim:

1. A seal blank of a type for use for forming a joint between overlapping portions of strapping and adapted to be nested with another similarly formed seal blank, comprising a back plate to which is joined a pair of divergent extending flanges along the lateral edges thereof, each flange having generally planar inner and outer faces, each outer face being formed with a first set of two step surfaces each at a different indented level below the plane of the outer face and extending substantially parallel to the outer face, a first recessed shoulder connecting the outer face to the first step surface and a second recessed shoulder connecting the first step surface with the second step surface, each inner face being formed with a second set of two step surfaces located respectively directly opposite the first set of two step surfaces and provided with embossed shoulders corresponding to and respectively opposite the recessed shoulders, the first recessed shoulder on one seal blank engaging an embossed shoulder on a similarly shaped seal blank with which said blank is nested to thereby hold the blanks together until they are moved endwise relative to each other to cause the engaged shoulders to pass by each other and disengage and separate the blanks.

2. A seal blank as defined by claim 1 characterized by, each face of each flange connecting to sloped cam surfaces intersecting the step surfaces, the cam surfaces on the front face of a flange on the one seal blank located to cam against the cam surfaces on the rear face of the similarly shaped seal blank with which said blank is nested to cause the flanges of the two nested seal blanks to be deflected by the camming action and permit said endwise movement of the nested seal blanks relative to each other.

3. A seal blank as defined by claim 2 characterized by, the slope of the cam surfaces with respect to the plane of the flanges they intersect being of approximately 13 degrees relative to the plane of the flanges.

4. A seal blank as defined by claim 1 characterized by, the second step surface and the respective opposite step surface on each flange extending to the free lateral edge of the flange.

5. A seal blank of a type for use for forming a joint between overlapping portions of strapping and adapted to be nested with another similarly formed seal blank, comprising a back plate to which is joined a pair of divergent extending flanges along the lateral edges thereof, each flange having generally planar inner and outer faces, each flange being provided with two offset portions each indented to a different level relative to the faces of the flange, the second offset portion extending to the free lateral edge of the flange with an embossed shoulder projecting from the inner face of the flange between the first offset portion and the second offset portion, an indented shoulder extending between the outer face of the flange and the first offset portion, the indented shoulder on one seal blank engaging the embossed shoulder on a similarly shaped blank with which said blank is nested to thereby hold the blanks together until they are moved endwise relative to each other to cause the engaged shoulders to pass by each other and disengage and separate the blanks.

6. A seal blank as defined by claim 5 characterized by, each flange connecting to sloped cam portions intersecting the offset portions, the cam portions providing cam surfaces on the front face of the flange on the one seal blank to cam against cam surfaces thereby provided on the rear face of a flange of the similarly shaped blank with which said blank is nested to cause the flanges of the two nested seal blanks to be deflected by the camrning action and permit said endwise movement of the nested seal blanks relative to each other.

7. A seal blank as defined by claim 5 characterized by, the slope of the cam portions with respect to the plane of the flange they intersect being of approximately 13 degrees relative to the plane of the flange.

8. A seal blank of a type for use for forming a joint between overlapping portions of strapping and adapted to be nested with another similarly formed seal blank, comprising a back plate to which is joined a pair of divergent extending flanges along the lateral edges thereof, each flange having generally planar inner and outer faces, each outer face being formed with a first set of two step surfaces each at a different indented level below the plane of the outer face and extending substantially parallel to the plane of the outer face, a first recessed shoulder extending longitudinally of the back plate and connecting the outer face to the first step surface, and a second recessed shoulder extending longitudinally of the back plate connecting the first step surface with the second step surface, each inner face being formed with a second set of two step surfaces located. respectively directly back-toback with the first set of two step surfaces and provided with embossed shoulders extending parallel to the recessed shoulders and corresponding to and respectively opposite the recessed shoulders, the first recessed shoulder on one seal blank interlockingly engaging an embossed shoulder on a similarly shaped seal blank with which said blank is nested to thereby hold the blanks together until they are moved endwise relative to each other to cause the engaged shoulders to pass by each other and disengage and separate the blanks.

K References Cited UNITED STATES PATENTS FOREIGN PATENTS 4/1964 Great Britain.

DONALD A. GRIFFIN, Primary Examiner. 

